<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>h1</title>
	</head>
	<body>
		<h1 align="center" 这是第一级标题</h1>
		<hr />
		<h2 align="right">这是第二级标题</h2>
		<h3 align="justify">这是第三级标题</h3>
	</body>
</html>